Magnetic plate



D. STEM MAGNETIC PLATE Filed Aug. 13 6 Fla INVENTOR DONALD asrsm r i This invention relates Patented Apr. 21, M 1953 MAGNETIC PLATE Donald E. Stem, San Francisco, Calif.

Application August 13, 1946, Serial No. 690,296

6 Claims.

to a magnetic plate and a method for making the same, and particularly to a magnetic plate used in magnetic traps or magnetic separators.

' r object of the invention is to provide magnetic plates for magnetic separators and the like, in such a manner that the material or substance "flowing over said magnetic plate is not collected.

any cracks or joints, and wherein the cleaning and sterilizing of the magnetic trap and plate is greatly facilitated.

A further object of the invention is to provide a magnetic plate and a method for making the same, so that perishable substances or materials -a magnetic plate and a method for making the same, wherein the magnetic elements are so connected together as to form a single unit with -a highly polished and smooth surface, and thereby obviate the necessity for additional covering for the handling of materials flowing through separators and the like.

Another object of the invention is to provide a magnetic plate wherein the magnetic field or plurality of fields are so offset and arranged with respect to the baffle of a trap as to act upon the materials flowing over it, preferably atthe area where the substance to be cleared is flowing away from said magnetic plate on the outlet side of the baflie; and where the material flows at a decreased velocity.

Another object of this invention is to provide a magnetic plate and method for making the same which is highly useful and simple in construction. Convenience of arrangement, lightness and comparative inexpense of manufacture are further objects which have been borne in mind in the production and development of the invention.

The essential features of the invention involved in the carrying out of the objects indicated are susceptible to modification, but a preferred embodiment of the invention is shown in the accompanying drawings, in which:

Fig. 1 is a side view ofa magnetic trap or separator partly in section showing a use of the magnetic plate of my invention;

-,.Fi'g. 2 is a view showing the parts of my mag- Iietic plate before the same are assembled to gether;

Fig. 3 shows the completed magnetic plate;

Fig. 4 is a perspective view of the magnetic plate completed, indicating the relative position of itselements; and,

Fig. 5 is a plan view of my magnetic plate with multiple magnetic fields.

Heretofore in magnetic traps and the like magnetic plates were used which were made by a pair of magnetic plates of suitable polarity separated by a non-magnetic element and clamped or bolted together. This construction resulted in a rough surface with transverse grooves or crevices; also at the points where the securing screws were placed other cavities or recesses formed, as well asseveral cavities and recesses at the clamps which held the pieces together. Usually these kind of traps are utilized in connection with liquids or semi-liquids for the purpose of removing metal particles during processing of the same. For instance, in connection with food products which in the course of proc essing are carried through lines, such a magnetic trap is interconnected so that the liquid or food product passes over the magnetic plate and allows the attracting of metal particles from the product to the surface of the magnetic plate. In the past, both food products and metal particles filled the cracks and recesses of the old type magnetic plate and thereby materially reduced its efliciency. Furthermore, food products and bacteria that might collect destroy the sterility required in such operations. Also, the cleaning of the old type magnetic plates was tedious and complicated. 3

In the method of making my magnetic plate, I make use of a pair of magnetic plates, and weld each of said magnetic plates to the opposite edges of a non-magnetic plate or strip therebetween so that the working surfaces thereof are at an even plane. After the welding and the formation of the securing holes and elements thereon, the entire working surface is highly polished as a unit so as to produce a single smooth surface without any cracks at any of the joints. In magnetic plates of the type herein shown, securing screws are also welded to the underside of each magnetic plate before the said polishing operation.

In the past it was also required to place a solid cover plate over the magnetic plate in order to have a smooth surface which, however, ma-

terially reduced the magnetic action andthe efliciency of such traps.

In my magnetic plate, magnetic pole plates 6 are formed so that-the inner edge of each plate zas shown in-Fig. 1. .:has alower flange or bottom opening 11 and the is a substantially straight transverse edge 1. The size of each plate is less than one-half of the entire magnetic plate to be used. A nonmagnetic connective strip 8 has opposed straight edges 9 which fit against the respective straight edges 1 of the pole plates 6. From the underside of each pole plate 6 extends a stud I2 which is threaded at its outer end l3 so as to be clamped to the usual magnet or the like. The pole plates 6 at their'edges '1 are welded to the adjacent edges 9 of the non-magnetic strip 8 so that the working surface of the united welded plate is on the same even level. After this working surface I4 is polished it presents an entirely smooth unitary surface. The studs l2 are integrally united with the respective pole plates 6. The article "of manufacture herein includes a pair of magnetic pole plates united together on the opposite edges of a non-magnetic plate or strip into a unitary solid working surface.

In use this unit formsgthe bottom of a trap 'Ihe'casing it of this trap plate herein is placed on the underside of said flange H; ;An insulating it of the plate I engages said flange IT, and suitable flanges l9 -ofa suitable magnet 2| are bolted .over the rim l8 and to the flange H. The magnet 2i has suitable bolt holes thereon through which the tuds. l2 extend. Nuts .22 in engagement with a threaded end l3 of the studs l2 clamp the magnet 2'! into the said plate unit. he respective poles of the magnet 2| are opposite the respective pole plates of the unit, so as to magnetize said pole plates at suitable polarities. Then the entire: magnet is locked inplace over suitable packing by bolts 23 and wing nuts 24.

In addition to the general method and struc ture heretofore described, my magnetic plate has the feature also of having the magnetic field offset in such a 'manner that the magnet acts upon the substance flowing over it at the point where the centrifugal force urges the metallic or heavier particles toward the magnetic plate and also where the flow is at a comparatively slower rate-of speed. Such condition exists, for instance, in'the trap illustrated in Fig. 1, on the outlet. side of the bafiie 25 which extends from the top of the trap 16 downwardly and toward the bottom opening I? so as to direct the substance or material flowing from an inlet 21 downwardly toward the plate heretofore described and then upwardly around the other side of the bafile 25 toward the outlet 28 of the trap. The

baffle 26 is spaced from the magnetic plate at a distance to provide a comparatively restricted area whereby an intermixture and whirling of the semi-fluid medium occ .1rs just above the trap. The material flowing at a variable speed into and away from the plate is in a best condition for depositing of the metallic particles on the magnet at said outlet side where the trapped particles remain comparatively undisturbed by the forceof fiow. As a matter of fact, as the liquid turns around to an upward flow to the outlet side of the baffle 25 at its turn centrifugal force assists somewhat for throwing the heavier metallic particles outwardly and toward the magnetic plate. If the magnetic field is provided at about that area it will accomplish a more perfect clearing of the material from such magnetic particles. This offsetting of the magnetic field is accomplished by offsetting the separator strip -8 toward .one .end .of. the completed plate.

w mar r a i -at ei m b ease e ts separator strip v32 .-of said plates.

4 is shown in Fig. 2, namely, one of the pole pieces 6 is made larger than the other so that when completed the non-magnetic strip of the completed plate is offset toward the pole plate 6 toward the left viewing Fig. 2. The combination thus accomplished with the trap results in an extension of the magnetic field over the outlet side of the trap with respect to the separating baffle therein.

Another form in which such offset magnetic fields maybe accomplished is shownin Fig. 5. In Fig. 5 there are four magnetic pole plates 3|, the transverse edges of which fit to the opposite edges of three non-magnetic separator strips 32 indicated in broken lines in Fig. 5. Over each adjacent pair of magnetic pole plates 3! is mounteda magnetindicated at 33 upon bolts in the manner heretofore described. In this manner two magnetic fields are provided on the plate which are on the opposite sides of the center One magnetic field can. operate, .for instance, in the trapof Fig. l on the intake side and another on the outlet side to take advantage of the whirling and .centrifugal forces which throw the -metallic par-- ticles closer to the magnetic field, having the weakest portion of the plate opposite the baffle. In many instances a plurality of such fields can be properly spaced in a single smooth plate with magnetic fields and separators properly located with respect to the flow of fluid in the trap or line where the fluid in the trap or line where the fluid or food is handled.

A further feature of the invention'is forming of the insulating, non-magnetic rim l-8 around the plate. A non-magnetic strip is welded to each edge of the plate and in the end stripsare formed the bolt holes -H for the securing bolts 23. The rim is is secured in place before polishing, so that it forms part of the polished plate surface and extends partly inside of the bottom opening [1 of the trap, yet has no crevice or cavity of any kind within which material could into a continuous smooth trapping surface in series, magnet means coacting with said strips to form .a plurality of magnetic fields .across said non-magnetic strips, and one of said non-magnetic strips and the magnetic field across the same being offset with respect to the middle of said flattened passage toward the :outlet of said body. I

2. In a magnetic trap of the character .de-- scribed, a body having an inlet and an outlet adapted to be .interconnected in a conduit system, a bafile portion between the inlet and the outlet in said body directing the flow toward the bottom of said body, and a bottom plate on said body, said baffle portion being spaced from said plate to form a passage from the inlet to the outlet of said body with an area restricted as to depth of flow, said plate including a plurality of spaced magnetic portions, and non-magnetic spacers between said portions; at least one, of said non-magnetic portions and the "magnetic field across the same being offset'with respect to said baflie portion and said restricted area toward said outlet.

3. In a sanitary food conveying device, the combination with a conduit and a trap chamber interrelated in said conduit and having means to provide a restricted passage in said chamber, of a magnetic plate located in said chamber and comprising a non-magnetic strip, and magnetic pole plates integrally united with each of the opposite side edges of said non-magnetic strip, the integral union lines along said side edges, the surfaces of said strip and of said magnetic pole plates facing toward said chamber forming an integrally continuous, uninterrupted unitary level smooth surface.

4. In a sanitary food conveying device, the combination with a conduit and a trap chamber interrelated in said conduit and having means to provide a restricted passage in said chamber, of a magnetic plate located in said chamber and comprising a non-magnetic flat strip and fiat magnetic pole plates integrally united with each of the opposite side edges of said strip, the surface of said composite magnetic plate facing toward said chamber being continuous, uninterrupted and level.

5. In a sanitary food conveying device, the combination with a conduit and a trap chamber interrelated in said conduit and having means to provide a restricted passage in said chamber, of a magnetic plate located in said chamber and comprising a non-magnetic flat strip and flat magnetic pole plates integrally united with each of the opposite side edges of said strip, and a unitary uninterrupted polished surface formed on the surface of said composite magnetic plate facing toward said chamber.

6. In a sanitary food conveying device, the combination with a conduit and a trap chamber interrelated in said conduit and having means to provide a restricted passage in said chamber, of a magnetic plate located in said chamber and comprising a plurality of alternate flat strips of non-magnetic material and flat magnetic pole plates welded together in edge to edge relation, each of said strips being between two of said pole plates, the surfaces of said strips and of said pole plates and the integral union lines along their joining side edges facing toward said chamber forming a continuous uninterrupted, smooth working surface.

DONALD E. STEM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 467,645 Richards Jan. 26, 1892 1,017,031 Wingaard Feb. 13, 1912 1,263,406 Hadley Apr. 23, 1918 1,471,624 Morton Oct. 23, 1923 1,507,006 Simmons Sept. 2, 1924 1,632,699 Denney June 14, 1927 1,704,783 Bing Mar. 12, 1929 1,706,721 Weyandt et a1 Mar. 26, 1929 1,778,910 Niven Oct. 21, 1930 2,053,177 Bower Sept. 1, 1936 2,086,164 Karasick July 6, 1937 2,179,625 Groden Nov. 14, 1939 2,187,240 Karasick Jan. 16, 1940 2,307,205 Ewald et. al. Jan. 5, 1943 2,346,193 Simmons Apr. 11, 1944 2,358,828 Ray Sept. 26, 1944 2,380,560 Urquhart July 31, 1945 2,464,628 Willard Mar. 15, 1949 FOREIGN PATENTS Number Country Date 563,333 Great Britain Aug. 9, 1944 673,688 France Oct. 8, 1929 

